Cascade Nonlinear Control of Photovoltaic System Connected to Single Phase Half Bridge Shunt Active Power Filter

This paper addresses the problem of controlling the single-phase shunt active power filter connected to the photovoltaic system through a half-bridge inverter and associated with non-linear loads. We seek the achievement of the two control objectives: i) compensation of the current harmonics and the reactive power absorbed by the nonlinear load in order to achieve power factor correction (PFC) and ii) regulation of the voltage across the PV system to guarantee the MPPT issue. To achieve the above control objectives, a two-loop cascaded nonlinear controller is developed using the backstepping design technique based on the averaged nonlinear model in the inner-loop and a filtered proportional-integral PI regulator with a well-known P&O algorithm in the outer-loop. The results are confirmed by simulations in Matlab\Simulink environment, which show that the proposed controller meets its objective.